The preparation method and apparatus according to the invention are for example designed to prepare a cell analysis slide as part of medical screening or diagnostics from cytological samples, such as Pap smears or other procedures.
The cells that are taken are placed in a sample vial, where the cells are placed in solution. Part of the cell solution is next taken and placed in an analysis container for diagnostic analysis of the sample. Document WO-2011/117523 for example describes such a preparation apparatus.
However, the analysis container obtained does not always make it possible to obtain a relevant and definite diagnosis, for example because the sample taken does not contain enough cells or because the cells of interest for diagnostic purposes are not in that sample. The obtained analysis container is then unusable.
In some applications, such as smear tests to screen for cervical cancer, cells are spread on analysis slides, and this spread must contain a satisfactory number of cells under the Bethesda classification, which is a classification for standardizing diagnostic smear test results. Each spread must thus contain more than 5000 cells.
In document FR-2,922,019, a method is disclosed for measuring the cell density done in the decanting chamber situated above the analysis slide. The density measured, for example by light diffraction, is subsequently compared to a threshold density corresponding to the minimum cell density of the spread on the analysis slide necessary to make a relevant diagnosis. Thus, if the density is below the threshold density, the method comprises an additional step for adjusting the cell density of the spread by adding, in the decanting chamber, a greater quantity of cell suspension taken from the vial than the standard quantity in order to produce a second representative smear slide.
However, this type of measurement in the decanting chamber has the drawback of being done after a first cell deposition. If there are not enough cells on the analysis slide, it is necessary to take the cell suspension again to produce a second smear. This therefore involves carrying out an additional complete step for depositing cells on the slide.